In industrial lasers used for welding or drilling, it is convenient to be able to pulse the optical beam. TEA lasers have been used to provide pulsed beams, as has Q-switching of cw (continuous wave) excited lasers. Also, optical chopping of a cw beam such as in a MOPA configuration or optically chopping the resonator internally have also been used. Each technique has advantages and limitations. Pulsed electrical power supplies are expensive, require voltages sufficient to break down the laser gas and require electrical power conditioning. Optically chopped MOPAs require isolation between the amplifier and the oscillator and are sensitive to self oscillation from feedback from work pieces. Chopping of the high power beam requires a chopper to withstand the effect of the high power beam. U.S. Pat. No. 4,512,021 illustrates passive Q-switching of a waveguide laser having a stable resonator and a coupled control cavity. U.S. Pat. No. 4,550,410 illustrates a coupled-cavity laser in which the coupled cavity serves to pass the output beam. This reference uses transmissive optics that pass more than 15% of the cavity power and therefore is not suitable for industrial power lasers.